<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
</head>
<body>
        <ul>
            <li>123</li>
        </ul>
        <script>
            var ul = document.querySelector('ul');
            var lili = document.createElement('li');
            ul.insertBefore(lili, ul.children[0]);
        </script>
</body>
</html>